This invention relates to helmets, particularly to helmets worn by drivers in open cockpit racing vehicles.
Helmets in various forms have been used throughout history to protect their wearer's heads. Full head helmets, replete with flip up face shields or visors have been famous since at least as early as the time European knights travelled about on horse back.
In addition to providing protection for the wearer's head, helmets have also been worn for aesthetic effect. In automobile racing aesthetics obviously take a back seat to the function of protecting the driver's head.
Other functions are also important, particularly in open cockpit racing such as Indianapolis 500 and Formula One style races. In such races, during which speeds greatly exceed 100 miles per hour, and sometime exceed 200 miles per hour, and in which a fraction of a second can be the difference between winning and losing, an important factor is aerodynamic drag (i.e., the resisting force exerted by air on a vehicle, which force tends to retard the vehicle's motion). We are all familiar with the recent efforts of designers of passenger automobiles to make their cars sleeker to reduce aerodynamic drag. Efforts in this regard are taken to much further lengths by designers of automobiles which are used solely for racing, since they are not constrained by the need to take into account making room for several passengers, child seats, groceries, and brief cases as passenger automobile designers must.
To reduce aerodynamic drag upon racing cars, designers have over the years reduced the size of the car chassis. As a result, in recent racing car designs, the driver's helmet has become more exposed to the effects of the air flowing through the cockpit area of the car. To the extent that the helmet is exposed to air flow, the helmet contributes to the aerodynamic drag exerted on the racing car and its contents (including the driver). In a field in which speed is so important, no ingredient which may reduce speed may be overlooked.
Also, to the extent that any aerodynamic drag is exerted on a helmet, the driver's head will be pushed back. A stop may be placed behind the driver's head, to reduce the strain on the driver's neck and shoulders that aerodynamic drag might create.
Modern helmets have been designed to reduce the drag force exerted on helmets. However, the configurations of some race cars and some prior art helmets, and the effect they have on the air flow path, potentially could result in an opposite force being exerted by the air flow on the helmets. That force, called thrust, causes the helmet, and the driver's head to which it is strapped, to be pulled forward. While the thrust force could be relatively low, it would be difficult, if not impossible to position an appropriate stop in the cockpit of a racing car to help the driver's efforts to keep the driver's head in its proper position. As a race goes on, the stress on the driver's neck and shoulders associated with the efforts to overcome thrust can cause severe discomfort for the driver.
Another aerodynamic force exerted on the helmet is lift. The helmet is pulled upward as a result of the air flowing around the helmet. This force also results in significant stress to the driver's neck and shoulders during a race.
Generally speaking, lift increases in proportion to the square of the increase in velocity of the car. So, as racing cars increase in speed, lift on a helmet becomes significantly more pronounced.
The air flow around the helmet also causes the helmet to pitch upward about the helmet's lateral axis (the axis perpendicular to both vertical and the longitudinal axis of the car), so that the front of the helmet tends to rise while the rear of the helmet tends to drop. This causes the driver's head to pitch as well, and also causes the helmet to tend to rotate relative to the driver's head. As a result, the driver endures additional stress and discomfort.
The foregoing problems are not the only ones causes by aerodynamic forces. The flow of air is not constant, instead it is quite turbulent. This turbulence causes the helmet to be subjected to fore and aft and side to side accelerations, or buffeting, and constitutes a further ingredient to a race car driver's strain and discomfort.
Under ideal circumstances, a helmet would have a neutral effect while being worn by a driver during a race. Even if a helmet had no direct effect on the performance of the race car (as discussed above, drag on a helmet can slow down the race car), stress and discomfort caused to the driver by aerodynamic effects may eventually result in a slower race being driven by the driver. In a worst case scenario, a driver's fatigue due to aerodynamic forces on the helmet could lead to a crash.
The helmet of the present invention reduces thrust, lift, pitch, and buffeting effects, and can be adjusted to accommodate various driver and race car combinations.